fs/exfat/dir.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
   4  */
   5
   6 #include <linux/slab.h>
   7 #include <linux/compat.h>
   8 #include <linux/bio.h>
   9 #include <linux/buffer_head.h>
  10
  11 #include "exfat_raw.h"
  12 #include "exfat_fs.h"
  13
  14 static int exfat_extract_uni_name(struct exfat_dentry *ep,
  15                 unsigned short *uniname)
  16 {
  17         int i, len = 0;
  18
  19         for (i = 0; i < EXFAT_FILE_NAME_LEN; i++) {
  20                 *uniname = le16_to_cpu(ep->dentry.name.unicode_0_14[i]);
  21                 if (*uniname == 0x0)
  22                         return len;
  23                 uniname++;
  24                 len++;
  25         }
  26
  27         *uniname = 0x0;
  28         return len;
  29
  30 }
  31
  32 static int exfat_get_uniname_from_ext_entry(struct super_block *sb,
  33                 struct exfat_chain *p_dir, int entry, unsigned short *uniname)
  34 {
  35         int i, err;
  36         struct exfat_entry_set_cache es;
  37         unsigned int uni_len = 0, len;
  38
  39         err = exfat_get_dentry_set(&es, sb, p_dir, entry, ES_ALL_ENTRIES);
  40         if (err)
  41                 return err;
  42
  43         /*
  44          * First entry  : file entry
  45          * Second entry : stream-extension entry
  46          * Third entry  : first file-name entry
  47          * So, the index of first file-name dentry should start from 2.
  48          */
  49         for (i = ES_IDX_FIRST_FILENAME; i < es.num_entries; i++) {
  50                 struct exfat_dentry *ep = exfat_get_dentry_cached(&es, i);
  51
  52                 /* end of name entry */
  53                 if (exfat_get_entry_type(ep) != TYPE_EXTEND)
  54                         break;
  55
  56                 len = exfat_extract_uni_name(ep, uniname);
  57                 uni_len += len;
  58                 if (len != EXFAT_FILE_NAME_LEN || uni_len >= MAX_NAME_LENGTH)
  59                         break;
  60                 uniname += EXFAT_FILE_NAME_LEN;
  61         }
  62
  63         exfat_put_dentry_set(&es, false);
  64         return 0;
  65 }
  66
  67 /* read a directory entry from the opened directory */
  68 static int exfat_readdir(struct inode *inode, loff_t *cpos, struct exfat_dir_entry *dir_entry)
  69 {
  70         int i, dentries_per_clu, num_ext, err;
  71         unsigned int type, clu_offset, max_dentries;
  72         struct exfat_chain dir, clu;
  73         struct exfat_uni_name uni_name;
  74         struct exfat_dentry *ep;
  75         struct super_block *sb = inode->i_sb;
  76         struct exfat_sb_info *sbi = EXFAT_SB(sb);
  77         struct exfat_inode_info *ei = EXFAT_I(inode);
  78         unsigned int dentry = EXFAT_B_TO_DEN(*cpos) & 0xFFFFFFFF;
  79         struct buffer_head *bh;
  80
  81         /* check if the given file ID is opened */
  82         if (ei->type != TYPE_DIR)
  83                 return -EPERM;
  84
  85         if (ei->entry == -1)
  86                 exfat_chain_set(&dir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
  87         else
  88                 exfat_chain_set(&dir, ei->start_clu,
  89                         EXFAT_B_TO_CLU(i_size_read(inode), sbi), ei->flags);
  90
  91         dentries_per_clu = sbi->dentries_per_clu;
  92         max_dentries = (unsigned int)min_t(u64, MAX_EXFAT_DENTRIES,
  93                                 (u64)EXFAT_CLU_TO_DEN(sbi->num_clusters, sbi));
  94
  95         clu_offset = EXFAT_DEN_TO_CLU(dentry, sbi);
  96         exfat_chain_dup(&clu, &dir);
  97
  98         if (clu.flags == ALLOC_NO_FAT_CHAIN) {
  99                 clu.dir += clu_offset;
 100                 clu.size -= clu_offset;
 101         } else {
 102                 /* hint_information */
 103                 if (clu_offset > 0 && ei->hint_bmap.off != EXFAT_EOF_CLUSTER &&
 104                     ei->hint_bmap.off > 0 && clu_offset >= ei->hint_bmap.off) {
 105                         clu_offset -= ei->hint_bmap.off;
 106                         clu.dir = ei->hint_bmap.clu;
 107                 }
 108
 109                 while (clu_offset > 0 && clu.dir != EXFAT_EOF_CLUSTER) {
 110                         if (exfat_get_next_cluster(sb, &(clu.dir)))
 111                                 return -EIO;
 112
 113                         clu_offset--;
 114                 }
 115         }
 116
 117         while (clu.dir != EXFAT_EOF_CLUSTER && dentry < max_dentries) {
 118                 i = dentry & (dentries_per_clu - 1);
 119
 120                 for ( ; i < dentries_per_clu; i++, dentry++) {
 121                         ep = exfat_get_dentry(sb, &clu, i, &bh);
 122                         if (!ep)
 123                                 return -EIO;
 124
 125                         type = exfat_get_entry_type(ep);
 126                         if (type == TYPE_UNUSED) {
 127                                 brelse(bh);
 128                                 break;
 129                         }
 130
 131                         if (type != TYPE_FILE && type != TYPE_DIR) {
 132                                 brelse(bh);
 133                                 continue;
 134                         }
 135
 136                         num_ext = ep->dentry.file.num_ext;
 137                         dir_entry->attr = le16_to_cpu(ep->dentry.file.attr);
 138                         exfat_get_entry_time(sbi, &dir_entry->crtime,
 139                                         ep->dentry.file.create_tz,
 140                                         ep->dentry.file.create_time,
 141                                         ep->dentry.file.create_date,
 142                                         ep->dentry.file.create_time_cs);
 143                         exfat_get_entry_time(sbi, &dir_entry->mtime,
 144                                         ep->dentry.file.modify_tz,
 145                                         ep->dentry.file.modify_time,
 146                                         ep->dentry.file.modify_date,
 147                                         ep->dentry.file.modify_time_cs);
 148                         exfat_get_entry_time(sbi, &dir_entry->atime,
 149                                         ep->dentry.file.access_tz,
 150                                         ep->dentry.file.access_time,
 151                                         ep->dentry.file.access_date,
 152                                         0);
 153
 154                         *uni_name.name = 0x0;
 155                         err = exfat_get_uniname_from_ext_entry(sb, &clu, i,
 156                                 uni_name.name);
 157                         if (err) {
 158                                 brelse(bh);
 159                                 continue;
 160                         }
 161                         exfat_utf16_to_nls(sb, &uni_name,
 162                                 dir_entry->namebuf.lfn,
 163                                 dir_entry->namebuf.lfnbuf_len);
 164                         brelse(bh);
 165
 166                         ep = exfat_get_dentry(sb, &clu, i + 1, &bh);
 167                         if (!ep)
 168                                 return -EIO;
 169                         dir_entry->size =
 170                                 le64_to_cpu(ep->dentry.stream.valid_size);
 171                         dir_entry->entry = dentry;
 172                         brelse(bh);
 173
 174                         ei->hint_bmap.off = EXFAT_DEN_TO_CLU(dentry, sbi);
 175                         ei->hint_bmap.clu = clu.dir;
 176
 177                         *cpos = EXFAT_DEN_TO_B(dentry + 1 + num_ext);
 178                         return 0;
 179                 }
 180
 181                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
 182                         if (--clu.size > 0)
 183                                 clu.dir++;
 184                         else
 185                                 clu.dir = EXFAT_EOF_CLUSTER;
 186                 } else {
 187                         if (exfat_get_next_cluster(sb, &(clu.dir)))
 188                                 return -EIO;
 189                 }
 190         }
 191
 192         dir_entry->namebuf.lfn[0] = '\0';
 193         *cpos = EXFAT_DEN_TO_B(dentry);
 194         return 0;
 195 }
 196
 197 static void exfat_init_namebuf(struct exfat_dentry_namebuf *nb)
 198 {
 199         nb->lfn = NULL;
 200         nb->lfnbuf_len = 0;
 201 }
 202
 203 static int exfat_alloc_namebuf(struct exfat_dentry_namebuf *nb)
 204 {
 205         nb->lfn = __getname();
 206         if (!nb->lfn)
 207                 return -ENOMEM;
 208         nb->lfnbuf_len = MAX_VFSNAME_BUF_SIZE;
 209         return 0;
 210 }
 211
 212 static void exfat_free_namebuf(struct exfat_dentry_namebuf *nb)
 213 {
 214         if (!nb->lfn)
 215                 return;
 216
 217         __putname(nb->lfn);
 218         exfat_init_namebuf(nb);
 219 }
 220
 221 /*
 222  * Before calling dir_emit*(), sbi->s_lock should be released
 223  * because page fault can occur in dir_emit*().
 224  */
 225 #define ITER_POS_FILLED_DOTS    (2)
 226 static int exfat_iterate(struct file *file, struct dir_context *ctx)
 227 {
 228         struct inode *inode = file_inode(file);
 229         struct super_block *sb = inode->i_sb;
 230         struct inode *tmp;
 231         struct exfat_dir_entry de;
 232         struct exfat_dentry_namebuf *nb = &(de.namebuf);
 233         struct exfat_inode_info *ei = EXFAT_I(inode);
 234         unsigned long inum;
 235         loff_t cpos, i_pos;
 236         int err = 0, fake_offset = 0;
 237
 238         exfat_init_namebuf(nb);
 239
 240         cpos = ctx->pos;
 241         if (!dir_emit_dots(file, ctx))
 242                 goto out;
 243
 244         if (ctx->pos == ITER_POS_FILLED_DOTS) {
 245                 cpos = 0;
 246                 fake_offset = 1;
 247         }
 248
 249         cpos = round_up(cpos, DENTRY_SIZE);
 250
 251         /* name buffer should be allocated before use */
 252         err = exfat_alloc_namebuf(nb);
 253         if (err)
 254                 goto out;
 255 get_new:
 256         mutex_lock(&EXFAT_SB(sb)->s_lock);
 257
 258         if (ei->flags == ALLOC_NO_FAT_CHAIN && cpos >= i_size_read(inode))
 259                 goto end_of_dir;
 260
 261         err = exfat_readdir(inode, &cpos, &de);
 262         if (err) {
 263                 /*
 264                  * At least we tried to read a sector.
 265                  * Move cpos to next sector position (should be aligned).
 266                  */
 267                 if (err == -EIO) {
 268                         cpos += 1 << (sb->s_blocksize_bits);
 269                         cpos &= ~(sb->s_blocksize - 1);
 270                 }
 271
 272                 err = -EIO;
 273                 goto end_of_dir;
 274         }
 275
 276         if (!nb->lfn[0])
 277                 goto end_of_dir;
 278
 279         i_pos = ((loff_t)ei->start_clu << 32) | (de.entry & 0xffffffff);
 280         tmp = exfat_iget(sb, i_pos);
 281         if (tmp) {
 282                 inum = tmp->i_ino;
 283                 iput(tmp);
 284         } else {
 285                 inum = iunique(sb, EXFAT_ROOT_INO);
 286         }
 287
 288         mutex_unlock(&EXFAT_SB(sb)->s_lock);
 289         if (!dir_emit(ctx, nb->lfn, strlen(nb->lfn), inum,
 290                         (de.attr & EXFAT_ATTR_SUBDIR) ? DT_DIR : DT_REG))
 291                 goto out;
 292         ctx->pos = cpos;
 293         goto get_new;
 294
 295 end_of_dir:
 296         if (!cpos && fake_offset)
 297                 cpos = ITER_POS_FILLED_DOTS;
 298         ctx->pos = cpos;
 299         mutex_unlock(&EXFAT_SB(sb)->s_lock);
 300 out:
 301         /*
 302          * To improve performance, free namebuf after unlock sb_lock.
 303          * If namebuf is not allocated, this function do nothing
 304          */
 305         exfat_free_namebuf(nb);
 306         return err;
 307 }
 308
 309 WRAP_DIR_ITER(exfat_iterate) // FIXME!
 310 const struct file_operations exfat_dir_operations = {
 311         .llseek         = generic_file_llseek,
 312         .read           = generic_read_dir,
 313         .iterate_shared = shared_exfat_iterate,
 314         .unlocked_ioctl = exfat_ioctl,
 315 #ifdef CONFIG_COMPAT
 316         .compat_ioctl = exfat_compat_ioctl,
 317 #endif
 318         .fsync          = exfat_file_fsync,
 319 };
 320
 321 int exfat_alloc_new_dir(struct inode *inode, struct exfat_chain *clu)
 322 {
 323         int ret;
 324
 325         exfat_chain_set(clu, EXFAT_EOF_CLUSTER, 0, ALLOC_NO_FAT_CHAIN);
 326
 327         ret = exfat_alloc_cluster(inode, 1, clu, IS_DIRSYNC(inode));
 328         if (ret)
 329                 return ret;
 330
 331         return exfat_zeroed_cluster(inode, clu->dir);
 332 }
 333
 334 int exfat_calc_num_entries(struct exfat_uni_name *p_uniname)
 335 {
 336         int len;
 337
 338         len = p_uniname->name_len;
 339         if (len == 0)
 340                 return -EINVAL;
 341
 342         /* 1 file entry + 1 stream entry + name entries */
 343         return ES_ENTRY_NUM(len);
 344 }
 345
 346 unsigned int exfat_get_entry_type(struct exfat_dentry *ep)
 347 {
 348         if (ep->type == EXFAT_UNUSED)
 349                 return TYPE_UNUSED;
 350         if (IS_EXFAT_DELETED(ep->type))
 351                 return TYPE_DELETED;
 352         if (ep->type == EXFAT_INVAL)
 353                 return TYPE_INVALID;
 354         if (IS_EXFAT_CRITICAL_PRI(ep->type)) {
 355                 if (ep->type == EXFAT_BITMAP)
 356                         return TYPE_BITMAP;
 357                 if (ep->type == EXFAT_UPCASE)
 358                         return TYPE_UPCASE;
 359                 if (ep->type == EXFAT_VOLUME)
 360                         return TYPE_VOLUME;
 361                 if (ep->type == EXFAT_FILE) {
 362                         if (le16_to_cpu(ep->dentry.file.attr) & EXFAT_ATTR_SUBDIR)
 363                                 return TYPE_DIR;
 364                         return TYPE_FILE;
 365                 }
 366                 return TYPE_CRITICAL_PRI;
 367         }
 368         if (IS_EXFAT_BENIGN_PRI(ep->type)) {
 369                 if (ep->type == EXFAT_GUID)
 370                         return TYPE_GUID;
 371                 if (ep->type == EXFAT_PADDING)
 372                         return TYPE_PADDING;
 373                 if (ep->type == EXFAT_ACLTAB)
 374                         return TYPE_ACLTAB;
 375                 return TYPE_BENIGN_PRI;
 376         }
 377         if (IS_EXFAT_CRITICAL_SEC(ep->type)) {
 378                 if (ep->type == EXFAT_STREAM)
 379                         return TYPE_STREAM;
 380                 if (ep->type == EXFAT_NAME)
 381                         return TYPE_EXTEND;
 382                 if (ep->type == EXFAT_ACL)
 383                         return TYPE_ACL;
 384                 return TYPE_CRITICAL_SEC;
 385         }
 386
 387         if (ep->type == EXFAT_VENDOR_EXT)
 388                 return TYPE_VENDOR_EXT;
 389         if (ep->type == EXFAT_VENDOR_ALLOC)
 390                 return TYPE_VENDOR_ALLOC;
 391
 392         return TYPE_BENIGN_SEC;
 393 }
 394
 395 static void exfat_set_entry_type(struct exfat_dentry *ep, unsigned int type)
 396 {
 397         if (type == TYPE_UNUSED) {
 398                 ep->type = EXFAT_UNUSED;
 399         } else if (type == TYPE_DELETED) {
 400                 ep->type &= EXFAT_DELETE;
 401         } else if (type == TYPE_STREAM) {
 402                 ep->type = EXFAT_STREAM;
 403         } else if (type == TYPE_EXTEND) {
 404                 ep->type = EXFAT_NAME;
 405         } else if (type == TYPE_BITMAP) {
 406                 ep->type = EXFAT_BITMAP;
 407         } else if (type == TYPE_UPCASE) {
 408                 ep->type = EXFAT_UPCASE;
 409         } else if (type == TYPE_VOLUME) {
 410                 ep->type = EXFAT_VOLUME;
 411         } else if (type == TYPE_DIR) {
 412                 ep->type = EXFAT_FILE;
 413                 ep->dentry.file.attr = cpu_to_le16(EXFAT_ATTR_SUBDIR);
 414         } else if (type == TYPE_FILE) {
 415                 ep->type = EXFAT_FILE;
 416                 ep->dentry.file.attr = cpu_to_le16(EXFAT_ATTR_ARCHIVE);
 417         }
 418 }
 419
 420 static void exfat_init_stream_entry(struct exfat_dentry *ep,
 421                 unsigned int start_clu, unsigned long long size)
 422 {
 423         memset(ep, 0, sizeof(*ep));
 424         exfat_set_entry_type(ep, TYPE_STREAM);
 425         if (size == 0)
 426                 ep->dentry.stream.flags = ALLOC_FAT_CHAIN;
 427         else
 428                 ep->dentry.stream.flags = ALLOC_NO_FAT_CHAIN;
 429         ep->dentry.stream.start_clu = cpu_to_le32(start_clu);
 430         ep->dentry.stream.valid_size = cpu_to_le64(size);
 431         ep->dentry.stream.size = cpu_to_le64(size);
 432 }
 433
 434 static void exfat_init_name_entry(struct exfat_dentry *ep,
 435                 unsigned short *uniname)
 436 {
 437         int i;
 438
 439         exfat_set_entry_type(ep, TYPE_EXTEND);
 440         ep->dentry.name.flags = 0x0;
 441
 442         for (i = 0; i < EXFAT_FILE_NAME_LEN; i++) {
 443                 if (*uniname != 0x0) {
 444                         ep->dentry.name.unicode_0_14[i] = cpu_to_le16(*uniname);
 445                         uniname++;
 446                 } else {
 447                         ep->dentry.name.unicode_0_14[i] = 0x0;
 448                 }
 449         }
 450 }
 451
 452 void exfat_init_dir_entry(struct exfat_entry_set_cache *es,
 453                 unsigned int type, unsigned int start_clu,
 454                 unsigned long long size, struct timespec64 *ts)
 455 {
 456         struct super_block *sb = es->sb;
 457         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 458         struct exfat_dentry *ep;
 459
 460         ep = exfat_get_dentry_cached(es, ES_IDX_FILE);
 461         memset(ep, 0, sizeof(*ep));
 462         exfat_set_entry_type(ep, type);
 463         exfat_set_entry_time(sbi, ts,
 464                         &ep->dentry.file.create_tz,
 465                         &ep->dentry.file.create_time,
 466                         &ep->dentry.file.create_date,
 467                         &ep->dentry.file.create_time_cs);
 468         exfat_set_entry_time(sbi, ts,
 469                         &ep->dentry.file.modify_tz,
 470                         &ep->dentry.file.modify_time,
 471                         &ep->dentry.file.modify_date,
 472                         &ep->dentry.file.modify_time_cs);
 473         exfat_set_entry_time(sbi, ts,
 474                         &ep->dentry.file.access_tz,
 475                         &ep->dentry.file.access_time,
 476                         &ep->dentry.file.access_date,
 477                         NULL);
 478
 479         ep = exfat_get_dentry_cached(es, ES_IDX_STREAM);
 480         exfat_init_stream_entry(ep, start_clu, size);
 481 }
 482
 483 static void exfat_free_benign_secondary_clusters(struct inode *inode,
 484                 struct exfat_dentry *ep)
 485 {
 486         struct super_block *sb = inode->i_sb;
 487         struct exfat_chain dir;
 488         unsigned int start_clu =
 489                 le32_to_cpu(ep->dentry.generic_secondary.start_clu);
 490         u64 size = le64_to_cpu(ep->dentry.generic_secondary.size);
 491         unsigned char flags = ep->dentry.generic_secondary.flags;
 492
 493         if (!(flags & ALLOC_POSSIBLE) || !start_clu || !size)
 494                 return;
 495
 496         exfat_chain_set(&dir, start_clu,
 497                         EXFAT_B_TO_CLU_ROUND_UP(size, EXFAT_SB(sb)),
 498                         flags);
 499         exfat_free_cluster(inode, &dir);
 500 }
 501
 502 void exfat_init_ext_entry(struct exfat_entry_set_cache *es, int num_entries,
 503                 struct exfat_uni_name *p_uniname)
 504 {
 505         int i;
 506         unsigned short *uniname = p_uniname->name;
 507         struct exfat_dentry *ep;
 508
 509         ep = exfat_get_dentry_cached(es, ES_IDX_FILE);
 510         ep->dentry.file.num_ext = (unsigned char)(num_entries - 1);
 511
 512         ep = exfat_get_dentry_cached(es, ES_IDX_STREAM);
 513         ep->dentry.stream.name_len = p_uniname->name_len;
 514         ep->dentry.stream.name_hash = cpu_to_le16(p_uniname->name_hash);
 515
 516         for (i = ES_IDX_FIRST_FILENAME; i < num_entries; i++) {
 517                 ep = exfat_get_dentry_cached(es, i);
 518                 exfat_init_name_entry(ep, uniname);
 519                 uniname += EXFAT_FILE_NAME_LEN;
 520         }
 521
 522         exfat_update_dir_chksum(es);
 523 }
 524
 525 void exfat_remove_entries(struct inode *inode, struct exfat_entry_set_cache *es,
 526                 int order)
 527 {
 528         int i;
 529         struct exfat_dentry *ep;
 530
 531         for (i = order; i < es->num_entries; i++) {
 532                 ep = exfat_get_dentry_cached(es, i);
 533
 534                 if (exfat_get_entry_type(ep) & TYPE_BENIGN_SEC)
 535                         exfat_free_benign_secondary_clusters(inode, ep);
 536
 537                 exfat_set_entry_type(ep, TYPE_DELETED);
 538         }
 539
 540         if (order < es->num_entries)
 541                 es->modified = true;
 542 }
 543
 544 void exfat_update_dir_chksum(struct exfat_entry_set_cache *es)
 545 {
 546         int chksum_type = CS_DIR_ENTRY, i;
 547         unsigned short chksum = 0;
 548         struct exfat_dentry *ep;
 549
 550         for (i = ES_IDX_FILE; i < es->num_entries; i++) {
 551                 ep = exfat_get_dentry_cached(es, i);
 552                 chksum = exfat_calc_chksum16(ep, DENTRY_SIZE, chksum,
 553                                              chksum_type);
 554                 chksum_type = CS_DEFAULT;
 555         }
 556         ep = exfat_get_dentry_cached(es, ES_IDX_FILE);
 557         ep->dentry.file.checksum = cpu_to_le16(chksum);
 558         es->modified = true;
 559 }
 560
 561 int exfat_put_dentry_set(struct exfat_entry_set_cache *es, int sync)
 562 {
 563         int i, err = 0;
 564
 565         if (es->modified)
 566                 err = exfat_update_bhs(es->bh, es->num_bh, sync);
 567
 568         for (i = 0; i < es->num_bh; i++)
 569                 if (err)
 570                         bforget(es->bh[i]);
 571                 else
 572                         brelse(es->bh[i]);
 573
 574         if (IS_DYNAMIC_ES(es))
 575                 kfree(es->bh);
 576
 577         return err;
 578 }
 579
 580 static int exfat_walk_fat_chain(struct super_block *sb,
 581                 struct exfat_chain *p_dir, unsigned int byte_offset,
 582                 unsigned int *clu)
 583 {
 584         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 585         unsigned int clu_offset;
 586         unsigned int cur_clu;
 587
 588         clu_offset = EXFAT_B_TO_CLU(byte_offset, sbi);
 589         cur_clu = p_dir->dir;
 590
 591         if (p_dir->flags == ALLOC_NO_FAT_CHAIN) {
 592                 cur_clu += clu_offset;
 593         } else {
 594                 while (clu_offset > 0) {
 595                         if (exfat_get_next_cluster(sb, &cur_clu))
 596                                 return -EIO;
 597                         if (cur_clu == EXFAT_EOF_CLUSTER) {
 598                                 exfat_fs_error(sb,
 599                                         "invalid dentry access beyond EOF (clu : %u, eidx : %d)",
 600                                         p_dir->dir,
 601                                         EXFAT_B_TO_DEN(byte_offset));
 602                                 return -EIO;
 603                         }
 604                         clu_offset--;
 605                 }
 606         }
 607
 608         *clu = cur_clu;
 609         return 0;
 610 }
 611
 612 static int exfat_find_location(struct super_block *sb, struct exfat_chain *p_dir,
 613                                int entry, sector_t *sector, int *offset)
 614 {
 615         int ret;
 616         unsigned int off, clu = 0;
 617         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 618
 619         off = EXFAT_DEN_TO_B(entry);
 620
 621         ret = exfat_walk_fat_chain(sb, p_dir, off, &clu);
 622         if (ret)
 623                 return ret;
 624
 625         /* byte offset in cluster */
 626         off = EXFAT_CLU_OFFSET(off, sbi);
 627
 628         /* byte offset in sector    */
 629         *offset = EXFAT_BLK_OFFSET(off, sb);
 630
 631         /* sector offset in cluster */
 632         *sector = EXFAT_B_TO_BLK(off, sb);
 633         *sector += exfat_cluster_to_sector(sbi, clu);
 634         return 0;
 635 }
 636
 637 #define EXFAT_MAX_RA_SIZE     (128*1024)
 638 static int exfat_dir_readahead(struct super_block *sb, sector_t sec)
 639 {
 640         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 641         struct buffer_head *bh;
 642         unsigned int max_ra_count = EXFAT_MAX_RA_SIZE >> sb->s_blocksize_bits;
 643         unsigned int page_ra_count = PAGE_SIZE >> sb->s_blocksize_bits;
 644         unsigned int adj_ra_count = max(sbi->sect_per_clus, page_ra_count);
 645         unsigned int ra_count = min(adj_ra_count, max_ra_count);
 646
 647         /* Read-ahead is not required */
 648         if (sbi->sect_per_clus == 1)
 649                 return 0;
 650
 651         if (sec < sbi->data_start_sector) {
 652                 exfat_err(sb, "requested sector is invalid(sect:%llu, root:%llu)",
 653                           (unsigned long long)sec, sbi->data_start_sector);
 654                 return -EIO;
 655         }
 656
 657         /* Not sector aligned with ra_count, resize ra_count to page size */
 658         if ((sec - sbi->data_start_sector) & (ra_count - 1))
 659                 ra_count = page_ra_count;
 660
 661         bh = sb_find_get_block(sb, sec);
 662         if (!bh || !buffer_uptodate(bh)) {
 663                 unsigned int i;
 664
 665                 for (i = 0; i < ra_count; i++)
 666                         sb_breadahead(sb, (sector_t)(sec + i));
 667         }
 668         brelse(bh);
 669         return 0;
 670 }
 671
 672 struct exfat_dentry *exfat_get_dentry(struct super_block *sb,
 673                 struct exfat_chain *p_dir, int entry, struct buffer_head **bh)
 674 {
 675         unsigned int dentries_per_page = EXFAT_B_TO_DEN(PAGE_SIZE);
 676         int off;
 677         sector_t sec;
 678
 679         if (p_dir->dir == DIR_DELETED) {
 680                 exfat_err(sb, "abnormal access to deleted dentry");
 681                 return NULL;
 682         }
 683
 684         if (exfat_find_location(sb, p_dir, entry, &sec, &off))
 685                 return NULL;
 686
 687         if (p_dir->dir != EXFAT_FREE_CLUSTER &&
 688                         !(entry & (dentries_per_page - 1)))
 689                 exfat_dir_readahead(sb, sec);
 690
 691         *bh = sb_bread(sb, sec);
 692         if (!*bh)
 693                 return NULL;
 694
 695         return (struct exfat_dentry *)((*bh)->b_data + off);
 696 }
 697
 698 enum exfat_validate_dentry_mode {
 699         ES_MODE_GET_FILE_ENTRY,
 700         ES_MODE_GET_STRM_ENTRY,
 701         ES_MODE_GET_NAME_ENTRY,
 702         ES_MODE_GET_CRITICAL_SEC_ENTRY,
 703         ES_MODE_GET_BENIGN_SEC_ENTRY,
 704 };
 705
 706 static bool exfat_validate_entry(unsigned int type,
 707                 enum exfat_validate_dentry_mode *mode)
 708 {
 709         if (type == TYPE_UNUSED || type == TYPE_DELETED)
 710                 return false;
 711
 712         switch (*mode) {
 713         case ES_MODE_GET_FILE_ENTRY:
 714                 if (type != TYPE_STREAM)
 715                         return false;
 716                 *mode = ES_MODE_GET_STRM_ENTRY;
 717                 break;
 718         case ES_MODE_GET_STRM_ENTRY:
 719                 if (type != TYPE_EXTEND)
 720                         return false;
 721                 *mode = ES_MODE_GET_NAME_ENTRY;
 722                 break;
 723         case ES_MODE_GET_NAME_ENTRY:
 724                 if (type & TYPE_BENIGN_SEC)
 725                         *mode = ES_MODE_GET_BENIGN_SEC_ENTRY;
 726                 else if (type != TYPE_EXTEND)
 727                         return false;
 728                 break;
 729         case ES_MODE_GET_BENIGN_SEC_ENTRY:
 730                 /* Assume unreconized benign secondary entry */
 731                 if (!(type & TYPE_BENIGN_SEC))
 732                         return false;
 733                 break;
 734         default:
 735                 return false;
 736         }
 737
 738         return true;
 739 }
 740
 741 struct exfat_dentry *exfat_get_dentry_cached(
 742         struct exfat_entry_set_cache *es, int num)
 743 {
 744         int off = es->start_off + num * DENTRY_SIZE;
 745         struct buffer_head *bh = es->bh[EXFAT_B_TO_BLK(off, es->sb)];
 746         char *p = bh->b_data + EXFAT_BLK_OFFSET(off, es->sb);
 747
 748         return (struct exfat_dentry *)p;
 749 }
 750
 751 /*
 752  * Returns a set of dentries.
 753  *
 754  * Note It provides a direct pointer to bh->data via exfat_get_dentry_cached().
 755  * User should call exfat_get_dentry_set() after setting 'modified' to apply
 756  * changes made in this entry set to the real device.
 757  *
 758  * in:
 759  *   sb+p_dir+entry: indicates a file/dir
 760  *   num_entries: specifies how many dentries should be included.
 761  *                It will be set to es->num_entries if it is not 0.
 762  *                If num_entries is 0, es->num_entries will be obtained
 763  *                from the first dentry.
 764  * out:
 765  *   es: pointer of entry set on success.
 766  * return:
 767  *   0 on success
 768  *   -error code on failure
 769  */
 770 static int __exfat_get_dentry_set(struct exfat_entry_set_cache *es,
 771                 struct super_block *sb, struct exfat_chain *p_dir, int entry,
 772                 unsigned int num_entries)
 773 {
 774         int ret, i, num_bh;
 775         unsigned int off;
 776         sector_t sec;
 777         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 778         struct buffer_head *bh;
 779
 780         if (p_dir->dir == DIR_DELETED) {
 781                 exfat_err(sb, "access to deleted dentry");
 782                 return -EIO;
 783         }
 784
 785         ret = exfat_find_location(sb, p_dir, entry, &sec, &off);
 786         if (ret)
 787                 return ret;
 788
 789         memset(es, 0, sizeof(*es));
 790         es->sb = sb;
 791         es->modified = false;
 792         es->start_off = off;
 793         es->bh = es->__bh;
 794
 795         bh = sb_bread(sb, sec);
 796         if (!bh)
 797                 return -EIO;
 798         es->bh[es->num_bh++] = bh;
 799
 800         if (num_entries == ES_ALL_ENTRIES) {
 801                 struct exfat_dentry *ep;
 802
 803                 ep = exfat_get_dentry_cached(es, ES_IDX_FILE);
 804                 if (ep->type != EXFAT_FILE) {
 805                         brelse(bh);
 806                         return -EIO;
 807                 }
 808
 809                 num_entries = ep->dentry.file.num_ext + 1;
 810         }
 811
 812         es->num_entries = num_entries;
 813
 814         num_bh = EXFAT_B_TO_BLK_ROUND_UP(off + num_entries * DENTRY_SIZE, sb);
 815         if (num_bh > ARRAY_SIZE(es->__bh)) {
 816                 es->bh = kmalloc_array(num_bh, sizeof(*es->bh), GFP_NOFS);
 817                 if (!es->bh) {
 818                         brelse(bh);
 819                         return -ENOMEM;
 820                 }
 821                 es->bh[0] = bh;
 822         }
 823
 824         for (i = 1; i < num_bh; i++) {
 825                 /* get the next sector */
 826                 if (exfat_is_last_sector_in_cluster(sbi, sec)) {
 827                         unsigned int clu = exfat_sector_to_cluster(sbi, sec);
 828
 829                         if (p_dir->flags == ALLOC_NO_FAT_CHAIN)
 830                                 clu++;
 831                         else if (exfat_get_next_cluster(sb, &clu))
 832                                 goto put_es;
 833                         sec = exfat_cluster_to_sector(sbi, clu);
 834                 } else {
 835                         sec++;
 836                 }
 837
 838                 bh = sb_bread(sb, sec);
 839                 if (!bh)
 840                         goto put_es;
 841                 es->bh[es->num_bh++] = bh;
 842         }
 843
 844         return 0;
 845
 846 put_es:
 847         exfat_put_dentry_set(es, false);
 848         return -EIO;
 849 }
 850
 851 int exfat_get_dentry_set(struct exfat_entry_set_cache *es,
 852                 struct super_block *sb, struct exfat_chain *p_dir,
 853                 int entry, unsigned int num_entries)
 854 {
 855         int ret, i;
 856         struct exfat_dentry *ep;
 857         enum exfat_validate_dentry_mode mode = ES_MODE_GET_FILE_ENTRY;
 858
 859         ret = __exfat_get_dentry_set(es, sb, p_dir, entry, num_entries);
 860         if (ret < 0)
 861                 return ret;
 862
 863         /* validate cached dentries */
 864         for (i = ES_IDX_STREAM; i < es->num_entries; i++) {
 865                 ep = exfat_get_dentry_cached(es, i);
 866                 if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
 867                         goto put_es;
 868         }
 869         return 0;
 870
 871 put_es:
 872         exfat_put_dentry_set(es, false);
 873         return -EIO;
 874 }
 875
 876 static int exfat_validate_empty_dentry_set(struct exfat_entry_set_cache *es)
 877 {
 878         struct exfat_dentry *ep;
 879         struct buffer_head *bh;
 880         int i, off;
 881         bool unused_hit = false;
 882
 883         /*
 884          * ONLY UNUSED OR DELETED DENTRIES ARE ALLOWED:
 885          * Although it violates the specification for a deleted entry to
 886          * follow an unused entry, some exFAT implementations could work
 887          * like this. Therefore, to improve compatibility, let's allow it.
 888          */
 889         for (i = 0; i < es->num_entries; i++) {
 890                 ep = exfat_get_dentry_cached(es, i);
 891                 if (ep->type == EXFAT_UNUSED) {
 892                         unused_hit = true;
 893                 } else if (!IS_EXFAT_DELETED(ep->type)) {
 894                         if (unused_hit)
 895                                 goto err_used_follow_unused;
 896                         i++;
 897                         goto count_skip_entries;
 898                 }
 899         }
 900
 901         return 0;
 902
 903 err_used_follow_unused:
 904         off = es->start_off + (i << DENTRY_SIZE_BITS);
 905         bh = es->bh[EXFAT_B_TO_BLK(off, es->sb)];
 906
 907         exfat_fs_error(es->sb,
 908                 "in sector %lld, dentry %d should be unused, but 0x%x",
 909                 bh->b_blocknr, off >> DENTRY_SIZE_BITS, ep->type);
 910
 911         return -EIO;
 912
 913 count_skip_entries:
 914         es->num_entries = EXFAT_B_TO_DEN(EXFAT_BLK_TO_B(es->num_bh, es->sb) - es->start_off);
 915         for (; i < es->num_entries; i++) {
 916                 ep = exfat_get_dentry_cached(es, i);
 917                 if (IS_EXFAT_DELETED(ep->type))
 918                         break;
 919         }
 920
 921         return i;
 922 }
 923
 924 /*
 925  * Get an empty dentry set.
 926  *
 927  * in:
 928  *   sb+p_dir+entry: indicates the empty dentry location
 929  *   num_entries: specifies how many empty dentries should be included.
 930  * out:
 931  *   es: pointer of empty dentry set on success.
 932  * return:
 933  *   0  : on success
 934  *   >0 : the dentries are not empty, the return value is the number of
 935  *        dentries to be skipped for the next lookup.
 936  *   <0 : on failure
 937  */
 938 int exfat_get_empty_dentry_set(struct exfat_entry_set_cache *es,
 939                 struct super_block *sb, struct exfat_chain *p_dir,
 940                 int entry, unsigned int num_entries)
 941 {
 942         int ret;
 943
 944         ret = __exfat_get_dentry_set(es, sb, p_dir, entry, num_entries);
 945         if (ret < 0)
 946                 return ret;
 947
 948         ret = exfat_validate_empty_dentry_set(es);
 949         if (ret)
 950                 exfat_put_dentry_set(es, false);
 951
 952         return ret;
 953 }
 954
 955 static inline void exfat_reset_empty_hint(struct exfat_hint_femp *hint_femp)
 956 {
 957         hint_femp->eidx = EXFAT_HINT_NONE;
 958         hint_femp->count = 0;
 959 }
 960
 961 static inline void exfat_set_empty_hint(struct exfat_inode_info *ei,
 962                 struct exfat_hint_femp *candi_empty, struct exfat_chain *clu,
 963                 int dentry, int num_entries, int entry_type)
 964 {
 965         if (ei->hint_femp.eidx == EXFAT_HINT_NONE ||
 966             ei->hint_femp.eidx > dentry) {
 967                 int total_entries = EXFAT_B_TO_DEN(i_size_read(&ei->vfs_inode));
 968
 969                 if (candi_empty->count == 0) {
 970                         candi_empty->cur = *clu;
 971                         candi_empty->eidx = dentry;
 972                 }
 973
 974                 if (entry_type == TYPE_UNUSED)
 975                         candi_empty->count += total_entries - dentry;
 976                 else
 977                         candi_empty->count++;
 978
 979                 if (candi_empty->count == num_entries ||
 980                     candi_empty->count + candi_empty->eidx == total_entries)
 981                         ei->hint_femp = *candi_empty;
 982         }
 983 }
 984
 985 enum {
 986         DIRENT_STEP_FILE,
 987         DIRENT_STEP_STRM,
 988         DIRENT_STEP_NAME,
 989         DIRENT_STEP_SECD,
 990 };
 991
 992 /*
 993  * @ei:         inode info of parent directory
 994  * @p_dir:      directory structure of parent directory
 995  * @num_entries:entry size of p_uniname
 996  * @hint_opt:   If p_uniname is found, filled with optimized dir/entry
 997  *              for traversing cluster chain.
 998  * @return:
 999  *   >= 0:      file directory entry position where the name exists
1000  *   -ENOENT:   entry with the name does not exist
1001  *   -EIO:      I/O error
1002  */
1003 int exfat_find_dir_entry(struct super_block *sb, struct exfat_inode_info *ei,
1004                 struct exfat_chain *p_dir, struct exfat_uni_name *p_uniname,
1005                 struct exfat_hint *hint_opt)
1006 {
1007         int i, rewind = 0, dentry = 0, end_eidx = 0, num_ext = 0, len;
1008         int order, step, name_len = 0;
1009         int dentries_per_clu;
1010         unsigned int entry_type;
1011         unsigned short *uniname = NULL;
1012         struct exfat_chain clu;
1013         struct exfat_hint *hint_stat = &ei->hint_stat;
1014         struct exfat_hint_femp candi_empty;
1015         struct exfat_sb_info *sbi = EXFAT_SB(sb);
1016         int num_entries = exfat_calc_num_entries(p_uniname);
1017
1018         if (num_entries < 0)
1019                 return num_entries;
1020
1021         dentries_per_clu = sbi->dentries_per_clu;
1022
1023         exfat_chain_dup(&clu, p_dir);
1024
1025         if (hint_stat->eidx) {
1026                 clu.dir = hint_stat->clu;
1027                 dentry = hint_stat->eidx;
1028                 end_eidx = dentry;
1029         }
1030
1031         exfat_reset_empty_hint(&ei->hint_femp);
1032
1033 rewind:
1034         order = 0;
1035         step = DIRENT_STEP_FILE;
1036         exfat_reset_empty_hint(&candi_empty);
1037
1038         while (clu.dir != EXFAT_EOF_CLUSTER) {
1039                 i = dentry & (dentries_per_clu - 1);
1040                 for (; i < dentries_per_clu; i++, dentry++) {
1041                         struct exfat_dentry *ep;
1042                         struct buffer_head *bh;
1043
1044                         if (rewind && dentry == end_eidx)
1045                                 goto not_found;
1046
1047                         ep = exfat_get_dentry(sb, &clu, i, &bh);
1048                         if (!ep)
1049                                 return -EIO;
1050
1051                         entry_type = exfat_get_entry_type(ep);
1052
1053                         if (entry_type == TYPE_UNUSED ||
1054                             entry_type == TYPE_DELETED) {
1055                                 step = DIRENT_STEP_FILE;
1056
1057                                 exfat_set_empty_hint(ei, &candi_empty, &clu,
1058                                                 dentry, num_entries,
1059                                                 entry_type);
1060
1061                                 brelse(bh);
1062                                 if (entry_type == TYPE_UNUSED)
1063                                         goto not_found;
1064                                 continue;
1065                         }
1066
1067                         exfat_reset_empty_hint(&candi_empty);
1068
1069                         if (entry_type == TYPE_FILE || entry_type == TYPE_DIR) {
1070                                 step = DIRENT_STEP_FILE;
1071                                 hint_opt->clu = clu.dir;
1072                                 hint_opt->eidx = i;
1073                                 num_ext = ep->dentry.file.num_ext;
1074                                 step = DIRENT_STEP_STRM;
1075                                 brelse(bh);
1076                                 continue;
1077                         }
1078
1079                         if (entry_type == TYPE_STREAM) {
1080                                 u16 name_hash;
1081
1082                                 if (step != DIRENT_STEP_STRM) {
1083                                         step = DIRENT_STEP_FILE;
1084                                         brelse(bh);
1085                                         continue;
1086                                 }
1087                                 step = DIRENT_STEP_FILE;
1088                                 name_hash = le16_to_cpu(
1089                                                 ep->dentry.stream.name_hash);
1090                                 if (p_uniname->name_hash == name_hash &&
1091                                     p_uniname->name_len ==
1092                                                 ep->dentry.stream.name_len) {
1093                                         step = DIRENT_STEP_NAME;
1094                                         order = 1;
1095                                         name_len = 0;
1096                                 }
1097                                 brelse(bh);
1098                                 continue;
1099                         }
1100
1101                         brelse(bh);
1102                         if (entry_type == TYPE_EXTEND) {
1103                                 unsigned short entry_uniname[16], unichar;
1104
1105                                 if (step != DIRENT_STEP_NAME ||
1106                                     name_len >= MAX_NAME_LENGTH) {
1107                                         step = DIRENT_STEP_FILE;
1108                                         continue;
1109                                 }
1110
1111                                 if (++order == 2)
1112                                         uniname = p_uniname->name;
1113                                 else
1114                                         uniname += EXFAT_FILE_NAME_LEN;
1115
1116                                 len = exfat_extract_uni_name(ep, entry_uniname);
1117                                 name_len += len;
1118
1119                                 unichar = *(uniname+len);
1120                                 *(uniname+len) = 0x0;
1121
1122                                 if (exfat_uniname_ncmp(sb, uniname,
1123                                         entry_uniname, len)) {
1124                                         step = DIRENT_STEP_FILE;
1125                                 } else if (p_uniname->name_len == name_len) {
1126                                         if (order == num_ext)
1127                                                 goto found;
1128                                         step = DIRENT_STEP_SECD;
1129                                 }
1130
1131                                 *(uniname+len) = unichar;
1132                                 continue;
1133                         }
1134
1135                         if (entry_type &
1136                                         (TYPE_CRITICAL_SEC | TYPE_BENIGN_SEC)) {
1137                                 if (step == DIRENT_STEP_SECD) {
1138                                         if (++order == num_ext)
1139                                                 goto found;
1140                                         continue;
1141                                 }
1142                         }
1143                         step = DIRENT_STEP_FILE;
1144                 }
1145
1146                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1147                         if (--clu.size > 0)
1148                                 clu.dir++;
1149                         else
1150                                 clu.dir = EXFAT_EOF_CLUSTER;
1151                 } else {
1152                         if (exfat_get_next_cluster(sb, &clu.dir))
1153                                 return -EIO;
1154                 }
1155         }
1156
1157 not_found:
1158         /*
1159          * We started at not 0 index,so we should try to find target
1160          * from 0 index to the index we started at.
1161          */
1162         if (!rewind && end_eidx) {
1163                 rewind = 1;
1164                 dentry = 0;
1165                 clu.dir = p_dir->dir;
1166                 goto rewind;
1167         }
1168
1169         /*
1170          * set the EXFAT_EOF_CLUSTER flag to avoid search
1171          * from the beginning again when allocated a new cluster
1172          */
1173         if (ei->hint_femp.eidx == EXFAT_HINT_NONE) {
1174                 ei->hint_femp.cur.dir = EXFAT_EOF_CLUSTER;
1175                 ei->hint_femp.eidx = p_dir->size * dentries_per_clu;
1176                 ei->hint_femp.count = 0;
1177         }
1178
1179         /* initialized hint_stat */
1180         hint_stat->clu = p_dir->dir;
1181         hint_stat->eidx = 0;
1182         return -ENOENT;
1183
1184 found:
1185         /* next dentry we'll find is out of this cluster */
1186         if (!((dentry + 1) & (dentries_per_clu - 1))) {
1187                 int ret = 0;
1188
1189                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1190                         if (--clu.size > 0)
1191                                 clu.dir++;
1192                         else
1193                                 clu.dir = EXFAT_EOF_CLUSTER;
1194                 } else {
1195                         ret = exfat_get_next_cluster(sb, &clu.dir);
1196                 }
1197
1198                 if (ret || clu.dir == EXFAT_EOF_CLUSTER) {
1199                         /* just initialized hint_stat */
1200                         hint_stat->clu = p_dir->dir;
1201                         hint_stat->eidx = 0;
1202                         return (dentry - num_ext);
1203                 }
1204         }
1205
1206         hint_stat->clu = clu.dir;
1207         hint_stat->eidx = dentry + 1;
1208         return dentry - num_ext;
1209 }
1210
1211 int exfat_count_dir_entries(struct super_block *sb, struct exfat_chain *p_dir)
1212 {
1213         int i, count = 0;
1214         int dentries_per_clu;
1215         unsigned int entry_type;
1216         struct exfat_chain clu;
1217         struct exfat_dentry *ep;
1218         struct exfat_sb_info *sbi = EXFAT_SB(sb);
1219         struct buffer_head *bh;
1220
1221         dentries_per_clu = sbi->dentries_per_clu;
1222
1223         exfat_chain_dup(&clu, p_dir);
1224
1225         while (clu.dir != EXFAT_EOF_CLUSTER) {
1226                 for (i = 0; i < dentries_per_clu; i++) {
1227                         ep = exfat_get_dentry(sb, &clu, i, &bh);
1228                         if (!ep)
1229                                 return -EIO;
1230                         entry_type = exfat_get_entry_type(ep);
1231                         brelse(bh);
1232
1233                         if (entry_type == TYPE_UNUSED)
1234                                 return count;
1235                         if (entry_type != TYPE_DIR)
1236                                 continue;
1237                         count++;
1238                 }
1239
1240                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1241                         if (--clu.size > 0)
1242                                 clu.dir++;
1243                         else
1244                                 clu.dir = EXFAT_EOF_CLUSTER;
1245                 } else {
1246                         if (exfat_get_next_cluster(sb, &(clu.dir)))
1247                                 return -EIO;
1248                 }
1249         }
1250
1251         return count;
1252 }